1. Bone Diseases and Abnormalities Jake Turner and Roger Deering

2. Learning Objectives 1.Explain how the structure of bone allows it to carry out its functions; (strong due to hydroxyapatite crystals, flexible due to collagen, good loadbearing due to honeycomb structure) 2.Compare the structure and function of cortical and trabecular bone; (Cortical = Strong, trabecular = weak, but quick to make) 3.Describe the importance of bone quality in addition to bone mineral content in overall bone strength; (if the structure is poor, the bone will be weak no matter what) 4.Describe the principles of osteoporosis prevention and management; (oestrogen, bisphosphonates, weight bearing, don’t give drugs that weaken bone) 5.Explain the physiological basis of the pharmacological management of osteoporosis; (keep calcium in the bone, ensure that osteoblast activity is at least equal to osteoclast activity) 6.Outline the mechanisms of action of drugs used to treat osteoporosis; (Calcium regulation, osteoblast / osteoclast regulation) 7.Give examples of common abnormalities of bone and explain the physiological basis of their development. (Rickets, osteoporosis, osteopenia, Paget’s disease of the bone, hyperparathyroidism)

3. What colour is bone?

4. Functions of bone Loadbearing Haematopoiesis Protection Mineral buffer Movement Hearing Acid base balance Fat storage

5. Rickets and Osteomalacia Rickets is ONLY in children Both cause softening of the bones, and abnormal bone growth. Causes Insufficient nutritional quantities or faulty metabolism of vitamin D or phosphorus Renal tubular acidosis Malnutrition during pregnancy Malabsorption syndrome Hypophosphatemia Chronic renal failure Tumour-induced osteomalacia Long-term anticonvulsant therapy Coeliac disease Cadmium poisoning, Itai-itai disease

6. Rickets and Osteomalacia Rickets is ONLY in children Both cause softening of the bones, and abnormal bone growth. Causes Vitamin D deficiency! Signs and symptoms: Weak bones Bone pain Muscle weakness Hypocalcaemia Compressed vertebrae Pelvic flattening Easy fracturing Bone softening Bending of bones

7. Hyperparathyroidism The function of parathyroid hormone is to increase blood calcium levels. This leads to weak bones, and possible calcium toxicity Primary, secondary and tertiary

8. Osteoporosis and osteopenia Diagnosed by: DEXA scans (Dual Energy X-ray Absorbitometry) If the bone density is more than 1 standard deviation from the average bone density of a 25 year old of the same gender then the diagnosis is osteopenia If the bone density is 2 or more standard deviations below the average bone density of a 25 year old of the same gender then the diagnosis is osteoporosis

10. Any Questions?